A selection of highlights culled from publications by HAO staff.
The bulk of the emission from the plasma called "transition region" plasma originates from structures energetically connected both to the chromosphere and corona. This result resolves decades of debate and opens the door to measuring magnetic energy and its evolution in the corona using transition region emission lines.
Prompted by a recent paper by Dima and Schad, we re-consider the problem of inferring magnetic properties of the corona using polarimetric observations of magnetic dipole (M1) lines.
Dikpati, et. al., derive magnetic toroids from surface magnetograms by employing a novel optimization method based on Trust Region Reflective algorithm.
A Case Study During a Minor Storm Period Under Solar Minimum Conditions: The dayside equatorial ionospheric electrodynamics exhibits strong variability driven simultaneously by highly changeable external forcings that originate from the Sun, magnetosphere, and lower atmosphere.
Design of a Highly Efficient Polychromatic Full-Stokes Polarization Modulator for the CRISP Imaging Spectrometer
In 2014 HAO built a polarimetric modulator for the CRISP instrument on the Swedish 1-m Solar Telescope in La Palma, using the principles of polychromatic modulation previously developed by HAO scientists. This paper discusses the processes by which the modulator was designed, built, and tested. The modulator was installed and had been in use since 2015. It is working at close to optimal efficiency and has produced considerable scientific output.
Accurate models of the spatial structure of ionospheric magnetic fields in the daily variation (DV) band (periods of approximately a few hours to a day) would enable use of magneto-variational methods for three-dimensional imaging of upper mantle and transition zone electrical conductivity. Constraints on conductivity at these depths, below what is typically possible with magnetotellurics, would in turn provide valuable constraints on mantle hydration and Earth’s deep water cycle.
Specified Dynamics Whole Atmosphere Community Climate Model with thermosphere-ionosphere eXtension (SD-WACCMX) simulations are used to investigate the solar migrating semidiurnal tide (SW2) around September equinox at middle to high latitudes in the Northern Hemisphere.
Venus’ atmosphere has a cloud layer (~40 km - ~70 km) that encompasses the whole planet that separates the lower atmosphere and upper atmosphere. Images of the clouds show planetary-scale wave patterns that exist from the equator to mid-latitudes and are thought to be a combination of Kelvin and Rossby waves.